Machine for molding a peripherally encapsulated product

ABSTRACT

A peripherally encapsulated product is molded by placing a piece of glass between mold clamping portions of movable closed bodies when the latter are in an open position. The bodies are heated and thermosetting polymeric material is placed upon one of the mold bodies outboard of a peripheral edge of a piece of glass. The glass is clamped and the mold bodies are closed creating compression forces which extrude the polymeric material into the annular cavity and into complete encapsulation of a peripheral edge of the piece of glass. The thermosetting polymeric material is cured, the mold bodies are opened and the product is removed therefrom.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of Ser. No. 09/277,756filed on Mar. 29, 1999, and now U.S. Pat. No. 6,558,596.

BACKGROUND OF THE INVENTION

It is conventional to insert a small panel or piece of glass into acavity of a multi-part mold and inject therein under elevatedtemperature and pressure polymeric/copolymeric material whichperipherally encapsulates a peripheral edge of the glass. An earlyinjection molding system of this type was used, for example, tomanufacture lens mounts, as disclosed in U.S. Pat. No. 2,266,169 in thename of Chester W. Crumrine which granted on Dec. 16, 1941. A lenselement is clamped between two centering plungers which hold the lenswith a peripheral edge thereof projecting into an annular cavity intowhich hot plastic is injected under pressure, cools and is subsequentlyremoved from the mold cavity in the form of a lens mount. Similarinjection molding to form peripherally encapsulated pieces of glass arefound in U.S. Pat. Nos. 2,559,860 and 3,971,841 issued to Howard G. Fayand Leon Rubinstein, respectively, on Jul. 10, 1951 and Jul. 27, 1976,respectively. Each of these two patents relate to lens systems forphotographic apparatus.

Larger pieces of glass have also been similarly provided with aninjection molded rim, encapsulation, or frame, as in U.S. Pat. Nos.4,626,185; 4,695,420 and 5,676,894 in the respective names of BernardMonnet, Charles E. Grawey et al. and Paul Specht, which issuedrespectively on Dec. 2, 1986; Sep. 2, 1987 and Oct. 14, 1997. Suchlarger encapsulated glass structures are typically used as curvedautomobile glass panels, printed circuit boards, window panes,structural paneling, and the like.

Another approach toward the manufacture of a frame member whichencapsulates a peripheral edge of a panel is found in U.S. Pat. No.5,329,686 in the name of Maurice A. Kildal et al. issued on Jul. 19,1994. In this patent a panel is placed between a frame member with anedge thereof being located in a recess while an integral lip of theframe member can be bent a distance sufficient to allow the panel to beperipherally clamped to the frame. Heretofore eye glass rims were soconstructed, as is evidenced by U.S. Pat. No. 3,399,018 in the name ofConrad L. Leblanc issued on Aug. 27, 1968.

Well prior to the latter disclosures, powdered material was placed in anannular cavity of a mold into which was inserted a piece of temperedglass, and upon the closing of the mold with the glass clamped andcentered therein, the powdered material melted and fused to a peripheryof the glass. Typical of this process was the utilization of “Bakelite”powder in the manner disclosed in U.S. Pat. No. 2,137,472 granted toLewis Jex-Blake Forbes on Nov. 22, 1938.

In lieu of powder which can be molded under heat and pressure, asdefined in the aforementioned patent, it had been common for years toutilize a ring or ring-like member of elastomeric material to form aseal for bearings or the like by placing the elastomeric member and ametal reinforcing member in a mold and closing the same under heat andpressure, as disclosed in U.S. Pat. No. 3,341,647 granted on Sep. 12,1967 to Douglas J. Aberle. The seal is extruded about an inner peripheryof the reinforcing member and is appropriately contoured to providedual-lip seals with excess material being squeezed radially outwardlyinto a cavity for collecting excess unwanted elastomer.

Somewhat similar to the latter process is that of manufacturing suchitems as loudspeaker diaphragms between a pair of mating molds byinserting therein the diaphragm and, adjacent an edge thereof, astrip-shaped base material consisting of rubber as a main compositionwith an associated foaming agent. During heat and pressure molding inthe cavity of the close mold the rubber is vulcanized and defines afoamed edge self-adhered to the outer periphery of the diaphragm, asdisclosed in U.S. Pat. No. 5,705,108 issued Jan. 6, 1998 to A. Nonogaki.

The assignee of the present invention has expertise in the injectionmolded encapsulation of tempered glass which is used primarily forshelving, particularly for refrigerators, as is evidenced by U.S. Pat.Nos. 5,273,354; 5,362,145; 5,403,084; 5,429,433; 5,441,338 and 5,454,638issued respectively on Dec. 28, 1993; Nov. 8, 1994; Apr. 4, 1995; Jul.4, 1995; Aug. 15, 1995 and Oct. 3, 1995, all assigned to the assignee ofthe present application.

Typically, such encapsulated shelves are manufactured in an injectionmold of the type disclosed in pending application Ser. No. 08/303,200filed on Sep. 8, 1994 in the names of Max Meier et al. In the latterdisclosure a tempered glass plate or panel has its peripheral edgelocated in a peripheral or annular cavity into which highly pressurized,hot, synthetic plastic polymeric/copolymeric material is injected and,upon subsequent cooling, the peripheral edge of the panel is bounded bya polymeric frame, rim or encapsulation which, since intended for use asa refrigerator shelf, has also integrally unitized thereto duringmolding opposite metallic shelf brackets.

A cooktop can be manufactured in much the same manner as that describedimmediately above, and a full disclosure thereof is found in commonlyassigned pending U.S. application Ser. No. 08/890,651 filed on Jul. 9,1997.

SUMMARY OF THE INVENTION

In keeping with the foregoing, a primary object of the present inventionis to provide a novel and unobvious method of manufacturing aperipherally encapsulated unit, such as a range oven door, which in useis subject to relatively high temperatures, particularly when an oven isbeing automatically cleaned under elevated temperatures. Range ovendoors are presently manufactured from metal which has a high degree ofrigidity and temperature stability, resist distortion, can withstandabuse, etc. However, conventional range oven doors are made of manydifferent pieces requiring separate formation, fabrication and assembly.Most commonly, such conventional range oven doors include a multipiece,inner, metal door frame assembly and a multipiece, oven door outer shellassembly. The latter are individually manufactured to include an ovendoor inner metal frame and an oven door outer shell, each of which has atempered glass viewing panel or window. A separate metallic connectingflange through which fasteners, pass is utilized for securing each glasspanel to its associated frame and/or shell. The outer shell is alsonecessarily primed and painted to match or complement the color of therange/oven. All of this is extremely time consuming and costly.

The prior art patents referenced earlier herein suggest the manufactureof a range oven door by injection molding polymeric/copolymeric materialunder heat and pressure to encapsulate a peripheral edge of a temperedglass sheet. Unfortunately, the polymeric/copolymeric plastic materialsavailable for injection molding cannot maintain tolerances, particularlyif heated to relatively high temperatures. In other words, suchmaterials generally lack relatively high hot rigidity at temperaturesassociated with baking, and even under relatively low temperatures thestrength to weight ratio is relatively low i.e., the polymeric materialis relatively weak and lacks the necessary strength, toughness andrigidity to withstand normal range oven door usage. Furthermore, whilesmaller products can be formed by injection molding polymeric materialabout the edge of a piece of glass, larger products create additionalmanufacturing problems, such as the control, reduction or elimination ofproduct shrinkage. Absent non-shrink or low-shrink characteristics, itwould be essentially impractical, if not impossible, to form aninjection molded encapsulated polymeric/copolymeric oven door, be it anoven door outer shell or an oven door inner frame or both and connectthe two together with repetitive accuracy. The individual shrinkage ofeach and the effects thereof one upon the other would essentiallypreclude either (a) inner and outer encapsulated units from beingmatchingly connected together or (b) either such encapsulated units frombeing matchingly connected to its multipart metal counterpart to form acommercially acceptable range oven door.

With the foregoing in mind, applicants have provided herewith a noveland unobvious method of molding a relatively large peripherallyencapsulated product, such as a range oven door and specifically an ovendoor outer shell thereof by placing a piece of tempered glass betweenmold clamping portions of mold bodies when the latter are in an openposition. One and preferably both of the mold bodies are heated andthermosetting polymeric material in the form of sheet molding compound(SMC) or bulk molding compound (BMC) is positioned upon one of theheated mold bodies within and about an area corresponding to an annularor peripheral mold cavity or chamber and outboard of a substantiallycontinuous peripheral edge of the piece of tempered glass. The moldbodies are then progressively closed to thereby create compressionforces upon the SMC/BMC which extrude the thermosetting polymericmaterial into the annular chamber and into complete peripheral edgeencapsulation of the continuous peripheral edge of the tempered glass,including opposite face surfaces and a peripheral edge surfacetherebetween. As the mold bodies close, surfaces thereof defineperipheral seals which prevent the SMC/BMC from escaping the annularmold cavity and instead the SMC/BMC is subject to relatively highcompression forces which assure that the mold cavity is completely andintimately filled. After curing the thermosetting polymeric materialunder such heat and pressure, the mold bodies are opened and theperipherally encapsulated product is removed.

The steps of the method just described, when performed in conjunctionwith the proper weight and distribution of the thermosetting polymericmaterial (SMC/BMC) upon the associated mold body, assures the molding ofa relatively dense, strong, tough and smooth-surfaced productessentially absent discernable flash, flash material, mold partinglines, voids, etc. Furthermore, since SMC/BMC can be effectively“non-shrink” compositions, as set forth in U.S. Pat. No. 3,947,615, theend product can be readily molded to exacting specifications and canreadily fulfil its function, preferably as an oven door outer shell ofan oven range door, for example.

In further accordance with the molding method of this invention, theannular mold cavity or chamber is contoured to impart to the oven doorouter shell an annular front wall bounding the panel of tempered glassand being integrally united thereto under the heat and pressure of the“extruded” SMC/BMC thermosetting material, while simultaneous therewitha flange-forming chamber portion of the annular mold cavity is likewisefilled with the “extrudate” under heat and pressure to form anintegrally molded peripheral flange. Additionally, the mold cavity iscontoured to provide reinforced fastener-receiving bosses andreinforcing ribs at corners of the oven door outer shell.

In further keeping with the present invention, during the closing of theannular mold chamber, opposing surfaces of the flange-forming moldcavity portion thereof meet and form a “sliding” outer peripheral sealwhich prevents the polymeric material from being “extruded” beyond theannular mold cavity under high molding pressures thus resulting in arelatively dense, smooth-surfaced, accurately dimensioned product.

The molded oven door outer shell constructed in accordance with theprocess of this invention is thus defined by a single piece of hotmolded integral thermosetting polymeric material, such as SMC or BMC,forming a generally polygonal frame member defined by a front wall of asubstantially annular configuration disposed substantially transverse toa peripheral wall or flange. The thermosetting polymeric moldingcompound has an inboardmost pressure “extruded” peripheral edge portionwhich encapsulates a peripheral edge of a piece of tempered glass,including opposite peripheral face surfaces and a peripheral edgesurface therebetween. This oven door outer shell, for example, can serveas a replacement for a conventional stainless steel oven door outershell and can be united to the conventional inner steel frame byconventional fasteners threaded into the integrally molded reinforcedfastener-receiving bosses at the corners of the polygonal frame member.The reinforcing ribs assure rigidity to the range oven door and/or theouter shell thereof over an extended lifetime of use.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a peripherally encapsulatedproduct, such as a range oven door, but preferably an outer shellthereof, and illustrates a generally polygonal annular frame memberdefined by a front annular wall and a peripheral flange with the frontannular wall defining an opening within which is housed a piece oftempered glass.

FIG. 2 is an enlarged rear perspective view of the peripherallyencapsulated product of FIG. 1, and illustrates integrally moldedreinforced fastener-receiving bosses and reinforcing ribs adjacentcorners of the frame member, and an inboard peripheral edge portion ofthe annular wall in gripping encapsulated relationship to the peripheraledge of the piece of tempered glass.

FIG. 3 is a highly enlarged fragmentary cross sectional view takengenerally along line 3—3 of FIG. 1, and illustrates details of the frontwall, the peripheral flange, a reinforcing rib and one of thefastener-receiving bosses of the oven door outer shell.

FIG. 4 is a cross sectional view taken through the outer shell of FIG.2, and illustrates the manner in which the tempered glass panel isretained therein and fasteners received in the bosses for uniting theouter shell to a conventional stainless steel range oven inner frame towhich another piece of tempered glass is assembled by a clamping ringand associated fasteners.

FIG. 5 is a perspective view of a mold in which the peripherallyencapsulated product or outer shell of FIGS. 1-4 is molded, andillustrates two mold bodies in the closed position thereof.

FIG. 6 is a slightly enlarged cross sectional view looking down alongline 6—6 of FIG. 5, and illustrates a generally polygonal centrallylocated spring biased floater or glass clamping mold portion surroundedby a generally outermost annular mold member having an upper surfaceupon which is positioned four stacks of SMC/BMC or equivalentthermosetting polymeric material.

FIG. 7 is a cross sectional view taken generally along line 7—7 of FIG.5, and illustrates an upper mold body in closed relationship to a lowermold body and defining therewith an annular mold cavity with a piece oftempered glass clamped between a central clamping mold portion of theupper mold body and the lower mold body floater incident to the moldingof the outer shell during which the SMC (or BMC) iscompression/extrusion molded to the configuration of the outer shellmore specifically illustrated in FIGS. 2, 3 and 4 of the drawings.

FIG. 8, which appears on the sheet of drawing containing FIG. 4, is anenlarged fragmentary cross sectional view taken generally along line 8—8of FIG. 6 and illustrates details of the mold bodies for forming eachreinforced fastener-receiving securing boss at each corner of the outershell.

FIG. 9 is an enlarged fragmentary vertical cross sectional view of theright-hand side of the mold illustrated in FIG. 7 in the open positionthereof, and illustrates the floater in its locked position, a piece oftempered glass resting upon the floater and SMC supported upon an upperannular surface of the lower mold body.

FIG. 10 is a cross sectional view of the mold substantially identical toFIG. 9, and illustrates the upper mold body being closed which causesthe heated SMC material to be compressed/extruded throughout theprogressively closing mold cavity, and a peripherally outermost“sliding” seal defined between contacting mold surfaces to prevent theSMC from being extruded beyond a terminal edge of a peripherallyoutermost flange forming cavity portion of the mold cavity.

FIG. 11 is a fragmentary cross sectional view, similar to FIGS. 9 and10, and illustrates the mold bodies completely closed during thethermosetting of the SMC under elevated temperature and pressure.

FIG. 12 is a fragmentary cross sectional view of the mold, similar toFIGS. 9, 10 and 11 of the drawings with the locking pin retracted andwithdrawn from the position illustrated at FIG. 9, and illustrates theejection of the cured outer shell by the upward movement of the floaterunder the influence of a plurality of ejector springs.

FIG. 13 is a highly enlarged cross sectional view of the mold bodies inthe closed position thereof corresponding to the position shown in FIG.11 and illustrates enlarged details of surfaces defining the mold cavityabsent SMC/BMC therein.

FIG. 14 is a fragmentary enlarged view of the mold bodies approachingthe closed position thereof corresponding to FIG. 10, and illustratesthe manner in which the tempered piece of glass is supported above anupper surface of the floater upon a bull nose or half round annularcushioning ring housed in an upwardly opening annular channel of thefloater.

FIG. 15 is a highly enlarged fragmentary cross sectional view of theencircled portion of FIG. 14, and illustrates the tempered glass panelelevated above a surface of the floater and in phantom outline thecompletely compressed position of the cushioning ring fully accommodatedwithin its associated upwardly opening channel.

FIG. 16 is a fragmentary cross sectional view, similar to FIG. 11, andillustrates another embodiment of the invention in which upper and lowermold bodies are contoured to form an integrally molded handle in a frontwall of another oven door outer shell of the invention.

FIG. 17 is a cross sectional view of the mold of FIG. 16, andillustrates the mold in the open position thereof incident to theejection and removal of the outer shell therefrom.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A peripherally encapsulated product molded in accordance with thisinvention is illustrated in FIGS. 1, 2 and 3 of the drawings, and isgenerally designated by the reference numeral 10.

The peripherally encapsulated product 10 is a range oven door, but morespecifically and preferably, an oven door outer shell 10 which is unitedto a conventional metal oven inner door frame assembly 9, (FIG. 4) of aconventional construction which will be described in more detailhereinafter.

The oven door outer shell 10 is comprised as a substantially singleintegral homogeneous piece of hot compression molded thermosettingpolymeric material (SMC or BMC) forming a generally polygonal annularframe member 11 defined by a front annular wall 12 and a peripheral wallor flange 13. The front wall 12 is disposed substantially transverse ornormal to the peripheral wall or flange 13 and borders the same aboutits entire periphery. A piece of generally polygonal, square orrectangular tempered glass or a glass panel 15 closes an opening 16defined by an innermost polygonal edge portion 17 of the front wall 12.A peripheral edge 18 (FIGS. 4, 11 and 12) of the tempered glass panel 15is totally encapsulated by the innermost peripheral edge portion 17 ofthe front wall 12 and is defined by an outermost border portion, flangeor edge 21 (FIGS. 4, 11 and 12), an innermost border portion, flange oredge 23 and a peripheral juncture portion 22 therebetween.

At each of four substantially identical corners 24 of the annular framemember 11 are means 25 (FIGS. 2, 3 and 8) in the form of inwardlyprojecting cylindrical fastener-receiving bosses for threadablyreceiving in cylindrical bores 26 thereof conventional fasteners F (FIG.4) which unite the oven door outer shell 10 to the oven door inner frameor assembly 9. Means 27 in the form of an inwardly directed reinforcingrib is provided at each corner 24 of the annular frame member 11extending substantially between each boss 25 and an associatedinboardmost corner 28 (FIG. 2) of the innermost polygonal edge portion17 of the front wall 12.

One or more relatively elongated vent slots 30 (FIGS. 1 and 2) can bepost-formed in upper and lower portions (unnumbered) of the peripheralflange 13, should such be found necessary or desirable. Additionally,holes 31 (FIGS. 1 and 2) can be formed in the front wall 12 during themolding of the annular frame member 11 or post-formed therein for thereceipt of fasteners for securing a handle (not shown) to the outershell 10. In lieu of the latter, the mold bodies to be describedhereinafter can be appropriately contoured to integrally mold a handlefrom a portion of the material of the front wall 12.

As is best illustrated in FIG. 4, the conventional oven door inner frameassembly 9 includes an inner polygonal annular frame 33 having fourgenerally hollow legs 32 through which the fasteners F pass forself-threading into the bores 26 of the bosses 25 (FIG. 3). The innerframe 33 has an outermost radially inwardly directed annular flange 34against which rests a peripheral edge 29 of a piece of tempered glass orglass panel 35 with a seal 36 sandwiched therebetween. An annularclamping collar 37 is fixed to the annular flange 34 of the inner frame33 by conventional fasteners F1.

Though not illustrated, the conventional oven door inner frame assembly9 is conventionally secured to pivot arms of an oven which are normallypivoted, counterbalanced and/or spring biased for pivoting movementbetween oven door open and oven door closed positions. In the closedposition of the oven door, the interior of the oven (not shown) can, ofcourse, be viewed through the tempered glass panel 15 of the door shell10 and the tempered glass panel 35 of the oven door inner frame assembly9.

A machine for molding the oven door outer shell 10 under heat andpressure from thermosetting SMC or BMC is illustrated in FIGS. 5-7, and9-14 of the drawings, and is generally designated by the referencenumeral 50.

The molding machine 50 includes a multi-part mold defined by at leasttwo relatively movable mold bodies, namely, a lower mold body 51 and anupper mold body 52 defining therebetween in a closed position agenerally polygonal annular mold cavity or chamber 60 (FIGS. 6, 7, 13and 14).

The lower mold body 51 is appropriately machined to define a generallyupwardly projecting annular mold chamber defining member 61 defined byan inner polygonal surface 62, (FIGS. 6, 7 and 13) an outer polygonalflange-forming surface 63 (FIG. 13) terminating at an annular upwardlyfacing end face 64 and opposite thereto a radius surface 65 blendingwith an upper relatively flat annular surface 66. The upper annularsurface 66 blends with an innermost radius surface 67 (FIG. 13) which inturn blends with an innermost peripheral annular surface 68. The surface68 in turn blends with an annular upwardly facing surface 69 which liesin a horizontal plane offset from but generally parallel to a horizontalplane of the annular surface 66. The surface 63 flares approximately 3°from a vertically outboardmost plane Pvo (FIG. 13) outboard thereof,while the surface 68 similarly flares 30 from a vertically innermostplane Pvi (FIG. 13) inboard thereof. In other words, the surfaces 63, 68and the respective planes Pvo, Pvi thereof are in upwardly convergingrelationship to each other which creates peripheral inboard and outboardseals, as will be described more fully hereinafter, to prevent SMC/BMCfrom being forced out of the annular mold chamber or cavity 60 evenprior to the molding bodies 51, 52 reaching their completely closedposition (FIGS. 7 and 11).

A generally polygonal or rectangular floater or clamping plate 70 (FIGS.6, 7 and 13) is mounted for vertical sliding movement within a so-calledinsert pocket (unnumbered) defined in part by the surface 62 of the moldchamber defining member 61. An outer peripheral surface 72 of thefloater 70 is in intimate sliding relationship with the surface 62 ofthe mold chamber defining member 61 and in part functions to close aperipherally innermost chamber portion or cavity portion 79 of theannular mold chamber or cavity 60 immediately adjacent an uppermostclamping surface 74 of the floater 70. The surface 74 of the floater orclamping plate 70 supports the tempered glass panel 15 during themolding of the oven door outer shell 10, as will be described more fullyhereinafter.

A plurality (six) of identical springs 80 (FIGS. 6, 7 and 12) normallybias the floater 70 to a position at which the upper surface 74 thereofis well above the surface 66 when the mold bodies 51 and 52 are open, asis illustrated in the product ejection position of FIG. 12 of thedrawings. This figure corresponds to the load position except, ofcourse, the space between the mold bodies is empty. However, beforeplacing the piece of tempered glass 15 upon the surface 74 of thefloater 70, the floater 70 is retracted against the bias of the springs80 in a conventional manner by, for example, placing a “dummy” insert orgauge upon the top surface 74 of the floater 70 corresponding inthickness to the thickness of the glass panel 15, closing the moldbodies 51, 52, and manually or automatically moving diametricallyopposing locking pins 91, 92 (FIGS. 7 and 9-11) into respective lockingrecesses 93, 94 of the floater 70. The mold bodies 51, 52 are thenopened, the gauge is removed therefrom, and subsequent molding can beinitiated by inserting the tempered glass panel 15 upon the surface 74of the floater 70, as will be described more fully hereinafter.

At each corner (unnumbered) of the mold chamber defining member 61 andin part defining the cavity 60 there is provided a taperedfrusto-conical upwardly opening bore 85 (FIGS. 6 and 8) which mergeswith a cylindrical bore 86 into each of which is positioned a stationaryor movable cylindrical rod 87 having a reduced cylindrical end portion88 above an annular face 89. The frusto-conical surface 85, thecylindrical portion 88 and the annular face 89 cooperatively form eachof the molded integral cylindrical fastener-receiving bosses 25 andassociated bores 26 (FIG. 3) of the frame member 11 during the moldingthereof. Diagonal upwardly opening grooves 96 (FIG. 6) open through theupper annular surface 66 of the mold chamber defining member 61 and moldtherein the reinforcing ribs 27 (FIG. 2) of the frame member 11 upon theoperation of the molding machine 50.

The upper mold body 52 defines the “female” cavity portion of theannular mold cavity 60 and is defined from the center outward by agenerally annular clamping surface or clamping portion 101 (FIGS. 6, 7and 13) parallel to the clamping surface 74 of the floater 70 whichcollectively define means for clamping the tempered glass plate 15therebetween. The annular surface 101 merges with an inboardmostperipheral surface 99 which merges with a radius surface 102 which inturn merges with an annular relatively flat surface 103 parallel to andspaced from the surface 66 of the lower mold body 51 and cooperativetherewith to form the front wall 12 of the oven door outer shell 10. Theannular surface 103 merges with a radius surface 104 adjacent and spacedfrom the radius surface 65 which in turn merges with a peripheralsurface 105 substantially parallel to the surface 63, including the 3°angle offset to the vertical and lying in a plane Pro parallel to theplane Pvo.

The molding machine 50 includes shims 121, 122 (FIGS. 9-11) carried bythe respective lower mold body 51 and the upper mold body 52 forachieving precise mold cavity dimensioning, particularly between thesurfaces 66, 103 and 74, 101 to accommodate the molding of differentthicknesses of the respective front wall 12 of the outer shell 10 anddifferent thicknesses of the tempered glass plate 15 associatedtherewith. Conventional fasteners 123 (FIG. 7) are utilized to replaceor add or change these shims 121, 122 as may be found necessary ordesirable.

Hot fluid, such as oil preferably at 475° F., is introduced into thelower mold body 51 of the mold 50 through a flexible pipe 130 andcirculates through ports (unnumbered) in the lower mold body 51 exitingtherefrom through a flexible pipe 131. Similarly, hot fluid isintroduced into the upper mold body 52 of the mold 50 through a flexiblepipe 132, circulates through ports (unnumbered) in the upper body 52 andis discharged through another flexible pipe 133.

Identical fluid motor means 140 (FIGS. 5 and 6) in the form ofconventional piston/cylinder motors are conventionally connected betweenand operate the mold bodies 51, 52 to reciprocate the same between thecompletely closed position (FIGS. 5, 7, 8 and 11) and the fully openposition thereof (FIG. 12) along a reciprocal path of travel Rpt (FIG.13).

The locking plungers 91, 92 are preferably held in their lockedpositions by manually rotated dogs 161, 162, respectively, (FIG. 5)though each plunger 91, 92 can be pneumatically moved into and removedfrom the respective tapered recesses 93, 94 in a manner clearly apparentfrom the drawings and FIG. 7 in particular.

Lastly, the upper surface or clamping surface 74 of the floater 70 isprovided with an annular upwardly opening recess or channel 170 (FIGS.14 and 15) which houses a bull-nosed or half-round resilient cushioningring 171 which in the open position of the mold bodies 51, 52 (FIGS. 14and 15) supports a lower surface (unnumbered) of the tempered glasspanel 15 slightly above the surface 74. The purpose of the annularcushioning ring or cushion 171 is to provide gradual application ofclamping forces against the tempered glass panel 15 during the closingof the mold bodies 51, 52 to preclude glass breakage, as might otherwiseoccur should tolerances be slightly “off.” However, by virtue of thecushioning ring 171, as the clamping surface 101 of the downwardlymoving upper mold body 52 contacts and initially exerts a downwardclosing force against the tempered glass panel 15, the cushioning ring170 is compressed and the clamping forces between the surfaces 74, 101are thereby progressively applied against the glass panel 15 until suchtime as the cushioning ring 171 is fully seated in the channel 170 (FIG.13). Obviously, no matter the cross section of the cushioning ring 171,it must be equal to or less than the cross section of the channel 170 tobe housed totally therein when completely compressed (phantom outline inFIG. 15).

Method of Operation

It is assumed that the molding machine 50 is heated, preferably byheating both the lower and upper mold bodies 51, 52, by circulatingtherethrough (and through the floater 70, if thought necessary ordesirable), hot fluid (oil) in the manner heretofore described. It isalso assumed that the mold bodies 51, 52 are in the open positionthereof with the locking pins 91, 92 holding the floater 70 in the“down” position shown in FIGS. 7, 9 and 11 of the drawings.

The tempered glass panel 15 is then manually or automatically positionedupon the cushioning ring 171, as shown in FIG. 9, which maintains alower surface (unnumbered) of the tempered glass panel 15 spacedslightly above the clamping surface 74 of the floater 70, as isillustrated in FIGS. 14 and 15.

Sheets of thermosetting SMC (FIGS. 6 and 9) are then placed upon theupper annular surface 66 of the mold chamber defining member 61 of thelower mold 51 substantially centrally thereof, outboard of theintermediate peripheral surface 68 and inboard of the outermostperipheral surface 63 (FIG. 9) The number of sheets of SMC, thethickness or thicknesses thereof, the lengths and widths, the locationand orientation upon the upper surface 66, and the total weight aredependent upon a number of factors, but chief among these is assuringthat the total uncompressed volume of all of the sheets SMC correspondin volume to the total volume of the completely closed mold chamber orcavity 60 to assure that the SMC is progressively and correctlycompression molded/extruded under heat (475° F.) and pressure (psi) uponthe closing of the mold bodies 51, 52 in a predetermined fashion toconsolidate totally within all cavity portions of the annular moldcavity 60 absent voids, leakage, marring, etc.

As the mold body moving means 140 move the mold bodies 51, 52 towardeach other along the path of travel Rpt which is normal to the surfaces66, 74, 101 and 103 and to the piece of glass 15, the heat and pressureapplied thereby to the SMC begins to melt, homogenize and laterally flowor extrude the SMC inwardly and outwardly in the manner best illustratedin FIG. 10 of the drawings. With particular reference to FIGS. 10 and13, the 3° rake or draft of the annular flange-forming surfaces 63, 63′,105 of the respective mold bodies 51, 52 come into contact and create anintimate peripheral seal S (FIGS. 10 and 13) about the entire peripheryof the outermost portion of the annular mold chamber 60. The flangeouter forming surface 105 essentially contacts the corner (unnumbered)define between the surface 63′ and the annular upwardly facing surface64 to form and maintain the seal S substantially at the relativeposition of the mold bodies 51, 52 illustrated in FIG. 10, and maintains(and expands the axial length) the peripheral seals until the moldbodies 51, 52 completely close (FIGS. 11 and 19). Thus, during thecontinued movement of the mold bodies 51, 52 toward each other, the SMCis extruded or caused to flow radially outwardly between the surfaces66, 103; 65, 104; 63, 105 and to but not beyond the annular upwardlyfacing surface 64 eventually forming the peripheral flange 13 absent anyleakage of the SMC beyond the annular seal S, as shown in FIG. 11.

From the position of the mold bodies 51, 52 shown in FIG. 10 until thecomplete closure thereof shown in FIG. 11, the SMC continues to extrudeor flow both inwardly and outwardly, into the frusto-conical recesses 85(FIGS. 6 and 8) and the rib-forming channels 96 (FIG. 6) untilsubsequently the annular surface 101 (FIG. 10) contacts the uppersurface (unnumbered) of the tempered glass panel 15. Prior to thissurface-to-surface contact, the SMC has not flowed under the closingpressure of the mold bodies 51, 52 leftward beyond the surfaces 62, 72and 99. However, during the final closure of the mold bodies 51, 52during which the cushioning ring 171 is compressed (FIG. 13), the finalrelative closing motion between the mold bodies 51, 52 extrudes the SMCinto the innermost peripheral mold cavity portion 79 defined generallyby the surfaces 68, 69, 72, 99 and 102. The SMC material thus extrudedinto the latter-defined capacity portion 79 completely encapsulates theedge 18 (FIGS. 4, 7 and 12) of the tempered glass panel 15 andintimately bonds thereto through the flange portions 21, 23 and theperipheral juncture portion 22 therebetween (FIG. 4).

The SMC (or BMC) material cures under the applied heat and pressure ofthe closed mold bodies 51, 52, and once curing is completed, the lockingdogs 161, 162 are pivoted 90° to release the locking pins or plungers91, 92, respectively, manually or automatically. The mold moving means140 are then operated to move the mold bodies 51, 52 progressively fromthe closed position (FIG. 11) to the fully open position (FIG. 12) atwhich time the springs 80 bias the floater 70 upwardly to its “up”position which automatically strips or ejects the cured outer shell 10(FIG. 12) from the now open annular mold cavity 60. The outer shell 10is removed, the floater 70 is moved back to the “down” position shown inFIG. 7 automatically or in the manual manner earlier described andlocked thereat by the locking pins 91, 92 and a new piece of temperedglass is placed upon the annular surface 74 of the floater 70 with SMCor BMC being again appropriately positioned upon the annular surface 66of the lower mold 52 incident to the molding of another outer shell 10.The outer shell 10 is then assembled to an inner door frame assembly 11in the manner heretofore described relative to FIG. 4 of the drawings.

The entire oven door (generally 10 in FIG. 4) is then appropriatelyunited in a conventional manner to conventionally pivoted springbalanced/counter balanced oven door arms of a conventional oven. Priorto the assembly of the outer shell 10 and the inner oven door frameassembly 9, the peripheral flange 13 of the outer oven door shell 10 canalso be post-formed with the vent slots 30, as was heretofore noted, andif desired, with the holes or bores 31.

Obvious details of the outer shell 10 can be varied, such as providingthe front wall 12 with an integral molded handle formed during themolding process just described and, of course, varying the size of theopening 16 in the front wall 12. Obviously, the SMC/BMC can be varied incolor to complement the particular oven/range to which the overall door(generally 10) is assembled. Likewise, though the inner oven door frameassembly 9 is peripherally exposed in FIG. 4, the flange 13 of the outershell 10 can be molded longer than illustrated to completely encapsulateand entirely peripherally bound the inner oven door frame assembly 9which could be more aesthetically pleasing depending upon specifics ofthe range or appliance with which the oven door (generally 10) isassociated.

The molding can also be altered somewhat from that described with thesame general result by, for example, opening the mold bodies 51, 52;releasing the plungers 91, 92, and maintaining the floater 70 springbiased upwardly in the position shown in FIG. 12 during the loading ofthe tempered glass sheet 15 upon the floater 70 and the application ofthe SMC upon the surface 66. The mold bodies 51, 52 would then berelatively moved toward each other during which time the surface 101 ofthe upper mold body 52 would contact the upper surface (unnumbered) ofthe tempered glass panel 15. Continued incremental closing movementbetween the mold bodies 51, 52 eventually results in the compression ofthe cushioning ring 171 into the annular upwardly opening channel 170resulting in the gripping/clamping of the thermal glass panel 15 betweenthe surfaces 101, 74. At this point in the closing operation the SMC (orBMC) upon the upper surface 66 of the lower mold body 51 has not beencontacted by the upper annular surface 66 of the upper mold body 52.However, as the mold bodies 51, 52 continue to progressively close theannular mold chamber 60, the floater 70 and the tempered glass panel 15descend to the final position thereof (FIG. 7). The SMC is eventuallycontacted, compressed and extruded during the final closing movement ofthe mold bodies 51, 52 resulting in the eventual formation of theannular seal S which occurs after, of course, the inboardmost portion ofthe annular molding chamber 60 has been completely closed atsubstantially the instant of clamping contact of the tempered glasspanel 15 between the surfaces 74, 101. Therefore, under continuedprogressive closing of the annular mold cavity 60, the SMC cannotextrude beyond the innermost surfaces 72, 99, 102 and as closingcontinues the SMC cannot extrude beyond the outermost terminal portionof the mold because of the peripheral seal S which remains operativeuntil the mold bodies 51, 52 are completely closed. The locking plungers91, 92 can be then moved into the latching recesses 93, 94,respectively, to the position shown in FIG. 7 until curing has completed(approximately 2-3 minutes under 400° F.-525° F., preferably 475° F.,oil-heated mold surface temperature). At the completion of curing thelocking plungers 91, 92 are retracted from the latching recesses orbores 93, 94, respectively, and the mold bodies 51, 52 are relativelyopened by movement along the path of travel Rpt with the resultantejection of the outer shell 10 by the upward bias movement of thefloater 70 under the force of the springs 80 in the manner heretoforedescribed.

Reference is made to FIGS. 16 and 17 of the drawings which illustrateanother molding machine 50′ which is substantially identical to themolding machine 50 heretofore described, and thus includes primednumerals to identify identical components.

The molding machine 50′ includes a multi-part mold defined by a lowermold body 51′ and an upper mold body 52′ defining therebetween in aclosed position a generally polygonal annular mold cavity or chamber60′.

The lower mold body 51′ is essentially identical to the lower mold body51 and, as is best illustrated in FIG. 17, includes identical moldcavity defining surfaces 63′-69′. However, the surface 66′ isinterrupted by an upwardly projecting handle-forming male mold portion200 defined by a relatively straight surface 201 disposed at a slightobtuse angle to the inboardmost portion of the surface 66′ and a curvedsurface 202. The surfaces 201, 202 extend lengthwise along the topportion of the front wall 12′ of the eventually formed outer shell 10′(FIG. 17) and the distance of such extension dictates the length of anintegrally molded handle 205. For example, the handle-forming moldportion 200 might have a length corresponding to the distance betweenthe openings 31, 31 (FIGS. 1 and 2) resulting in the formation of theintegrally molded handle 205 (FIG. 17) corresponding in length to thedistance between the openings 31, 31. However, since the handle 205 isintegrally molded, the top wall 12′ (FIG. 17) would be devoid of theopenings 31 which are rendered unnecessary by the integral molding ofthe handle or handle portion 205.

The upper mold body 52′ is formed of two mold parts or mold portions,namely, an outer annular mold part 52″ and an inner annular polygonalmold part 52′″ having respective surfaces 206, 207 which in the closedposition of the mold bodies 51′, 52′ abut each other and abut thesurface 201 of the handle forming mold portion 200.

In the open position of the mold 50′ (FIG. 17), appropriate SMC/BMCthermosetting material is seated atop the surface 66′ both to the leftand to the right of the handle-forming mold portion 200. Suchthermosetting material might also be placed along the surface 202adjacent its juncture with the surface 66′, but the specific location ofthe SMC is such that upon the closing of the mold cavity 60′ (FIG. 16),the SMC material will be compression molded and extruded in the mannerheretofore described with respect to the mold 50 and, of course, willalso completely fill a handle-forming chamber portion 210′ defined bythe surface 202 of the male handle-forming mold portion 200 and acomplementary contoured female cavity surface 211 of the mold part 52″.

While different SMC and BMC compositions can be utilized in conjunctionwith the present invention, those reduced to practice by the assignee ofthe present invention includes specifically SMC 1840 manufactured byBulk Molding Compounds, Inc. of 1600 Powis Corp., West Chicago, Ill.60185. The BMC material reduced to practice in accordance with thisinvention is BMC 130, also available from Bulk Molding Compounds, Inc.

Although preferred embodiments of the invention have been specificallyillustrated and described herein, it is to be understood that minorvariations may be made in the method and article without departing fromthe spirit and scope of the invention, as defined in the appendedclaims.

What is claimed is:
 1. A machine for molding a peripherally encapsulatedproduct comprising: (a) a multi-part mold including at least tworelatively movable mold bodies defining in a closed position thereof asubstantially continuous annular inwardly opening mold chamber, (b) saidmold chamber including an innermost annular mold chamber portion intowhich projects the peripheral edge portion of the piece of glass, amedial annular mold chamber portion outboard of said innermost annularmold chamber portion and an outermost peripheral mold chamber portiondisposed in substantially transverse relationship to said medial annularmold chamber portion; (c) means inboard of the annular mold chamber forclamping a piece of glass in substantially precise relationship to saidannular inwardly opening mold chamber in the closed position of saidmold bodies, (d) means for heating at least one of the mold bodies, (e)means for relatively moving said clamping means toward each other toclamp a piece of glass therebetween, (f) means for relatively movingsaid mold bodies toward each other to the closed position in which aperipheral edge portion of the piece of glass projects into the annularmold chamber and thermosetting polymeric material located between themold bodies substantially in the medial annular mold chamber portion inan open position thereof is subjected to compression forces of theclosing mold bodies which extrude the thermosetting polymeric materialinto complete encapsulation of the glass peripheral edge portionincluding opposite surfaces and a peripheral edge surface therebetweenand into the outermost peripheral mold chamber portion to form a flangedisposed substantially transverse to the piece of glass, and (g) saidmold bodies moving means being operative to move said mold bodies totheir open position after the thermosetting polymeric material has curedunder heat and pressure while the mold is in its closed position wherebythe molded peripherally encapsulated product can be subsequently removedfrom the open mold chamber.
 2. The molding machine as defined in claim 1including means for effecting an outermost peripheral seal between saidmold bodies before the total closure of said annular mold chamber andbefore the complete extrusion of the thermosetting polymeric material.3. The molding machine as defined in claim 1 wherein said mold bodiesand said clamping means move relatively along a path of travelsubstantially normal to a plane of the piece of glass.
 4. The moldingmachine as defined in claim 1 wherein a first of said mold bodiesincludes an annular mold surface blending with a radius mold surfacewhich in turn blends with a peripheral mold surface disposed insubstantially transverse relationship to said annular mold surface, anda second of said mold bodies includes an outermost annular mold surfaceblending with innermost and outermost radius mold surfaces which in turnblend respectively with an innermost annular mold surface and anoutermost peripheral mold surface disposed in substantially transverserelationship to said outermost annular mold surface.
 5. The moldingmachine as defined in claim 1 wherein a first of said mold bodiesincludes an annular mold surface blending with a radius mold surfacewhich in turn blends with a peripheral mold surface disposed insubstantially transverse relationship to said annular mold surface, asecond of said mold bodies includes an outermost annular mold surfaceblending with innermost and outermost radius mold surfaces which in turnblend respectively with an innermost annular mold surface and anoutermost peripheral mold surface disposed in substantially transverserelationship to said outermost annular mold surface, and said innermostand outermost annular mold surfaces are disposed in substantially offsetplanes.
 6. The molding machine as defined in claim 1 wherein a first ofsaid mold bodies includes an annular mold surface blending with a radiusmold surface which in turn blends with a peripheral mold surfacedisposed in substantially transverse relationship to said annular moldsurface, a second of said mold bodies includes an outermost annular moldsurface blending with innermost and outermost radius mold surfaces whichin turn blend respectively with an innermost annular mold surface and anoutermost peripheral mold surface disposed in substantially transverserelationship to said outermost annular mold surface, and said innermostand outermost annular mold surfaces are disposed in substantially offsetsubstantially parallel planes.
 7. The molding machine as defined inclaim 1 wherein a first of said mold bodies includes an annular moldsurface blending with a radius mold surface which in turn blends with aperipheral mold surface disposed in substantially transverserelationship to said annular mold surface, a second of said mold bodiesincludes an outermost annular mold surface blending with innermost andoutermost radius mold surfaces which in turn blend respectively with aninnermost annular mold surface and an outermost peripheral mold surfacedisposed in substantially transverse relationship to said outermostannular mold surface, and said first-mentioned and outermost annularmold surfaces are disposed in substantially spaced parallel relationshipto each other in the closed position of the mold.
 8. The molding machineas defined in claim 1 wherein a first of said mold bodies includes anannular mold surface blending with a radius mold surface which in turnblends with a peripheral mold surface disposed in substantiallytransverse relationship to said annular mold surface, a second of saidmold bodies includes an outermost annular mold surface blending withinnermost and outermost radius mold surfaces which in turn blendrespectively with an innermost annular mold surface and an outermostperipheral mold surface disposed in substantially transverserelationship to said outermost annular mold surface, and saidfirst-mentioned and outermost peripheral mold surfaces are disposed insubstantially spaced parallel relationship to each other in the closedposition of the mold.
 9. The molding machine as defined in claim 1wherein a first of said mold bodies includes an annular mold surfaceblending with a radius mold surface which in turn blends with aperipheral mold surface disposed in substantially transverserelationship to said annular mold surface, a second of said mold bodiesincludes an outermost annular mold surface blending with innermost andoutermost radius mold surfaces which in turn blend respectively with aninnermost annular mold surface and an outermost peripheral mold surfacedisposed in substantially transverse relationship to said outermostannular mold surface, said first-mentioned and outermost annular moldsurfaces are disposed in substantially spaced parallel relationship toeach other in the closed position of the mold, and said first-mentionedand outermost peripheral mold surfaces are disposed in generally spacedparallel relationship to each other in the closed position of the mold.10. The molding machine as defined in claim 1 wherein said mold chamberincludes an innermost annular mold chamber portion into which projectsthe peripheral edge portion of the piece of glass and an outermostperipheral mold chamber portion disposed in substantially transverserelationship to said innermost annular mold chamber portion, and saidinnermost annular mold chamber portion is defined in part by outermostperipheral mold surfaces of said clamping means.
 11. The molding machineas defined in claim 4 wherein said mold bodies and said clamping meansmove relatively along a path of travel substantially normal to a planeof the piece of glass.
 12. The molding machine as defined in claim 5wherein said mold bodies and said clamping means move relatively along apath of travel substantially normal to a plane of the piece of glass.13. The molding machine as defined in claim 6 wherein said mold bodiesand said clamping means move relatively along a path of travelsubstantially normal to a plane of the piece of glass.
 14. The moldingmachine as defined in claim 7 wherein said mold bodies and said clampingmeans move relatively along a path of travel substantially normal to aplane of the piece of glass.
 15. The molding machine as defined in claim8 wherein said mold bodies and said clamping means move relatively alonga path of travel substantially normal to a plane of the piece of glass.16. The molding machine as defined in claim 1 wherein said outermostperipheral mold chamber portion is disposed in substantially normalrelationship to said medial annular mold chamber portion.